If you do not have a PayPal account, no problem. Just click the continue link. It is a little hard to see on the first page you land on after clicking the payment button. You will be taken to a credit card payment page. Follow the instructions. It is secure and easy.
If you have an account, just log in and choose the method of payment.
Paying an invoice, click the invoice payment image or link. You will be taken to a secure page. Put the total invoice amount in the form provided and click the update totals box.. Then proceed to log in or click the continue link if you do not have a paypal account.
Once you click the Review Order and Continue button, you will see the final order screen. Just type your invoice number in the ext area along with any message you like and follow the prompts to complete the process.